This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-206764, filed Jul. 7, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an inductive coupling plasma processing apparatus for applying plasma processing such as dry etching to substrates to be treated such as a liquid crystal display (LCD) substrate by an inductive coupling plasma.
2. Description of the Related Art
In general, in an LCD manufacturing process, an LCD glass substrate as a substrate to be treated is frequently subjected to etching, sputtering, chemical vapor-phase development (CVD) or another plasma processing. Various plasma processing apparatuses for performing the plasma processing have been used, and among these an inductive coupling plasma (ICP) processing apparatus is known which can generate a high-density plasma in an area inside a processing chamber.
Typically in the inductive coupling plasma processing apparatus, a ceiling of a processing chamber (area in the processing chamber) for performing the plasma processing in a vacuum is constituted of a dielectric wall portion, and a high-frequency (RF) antenna is disposed on the portion. Moreover, when a high-frequency power is supplied to the high-frequency antenna, an induction field is formed in the processing chamber. A process gas introduced into the processing chamber is formed into a plasma by the induction field, and etching or another processing is applied by an action of the plasma.
One problem of the inductive coupling plasma processing apparatus is the adverse influence of particles generated in the processing chamber on the material to be treated. In this case, reaction byproducts generated in the substrate processing chamber when a processing is performed are deposited onto the dielectric wall portion or the like, and may end up on the surface of the substrate. During an etching process the byproduct acts as a mask, causing a problem in which the area under the mask cannot be etched. Moreover, when a film forming process is performed, a film is also deposited on the reaction product, and included in the formed film. Therefore, problems occur such as disconnections of a wiring pattern and structural defects of a circuit device.
As a technique for preventing the reaction product from adhering to the substrate, as disclosed, for example, in Jpn. Pat. Appln. KOKAI Publication Nos. 11-45878 and 9-199487, a technique of disposing a heater or the like in the dielectric wall portion and heating the dielectric wall portion at a predetermined temperature is known. However, when the dielectric wall portion is heated and temperature is adjusted to bring the portion to a high-temperature state as in the conventional techniques, the thermal capacity of the dielectric wall portion is large, heat dissipation toward an atmospheric side is large, power consumption increases, and energy efficiency is deteriorated.
In recent years, there have been demands for larger LCD display screens, therefore, the LCD glass substrate has consequently also enlarged. For this, a huge substrate whose side is as large as 1 m is necessary. Accordingly, the processing apparatus is enlarged in size, the dielectric wall portion has also to be enlarged, the power consumption increases further, and the energy efficiency is remarkably deteriorated.
On the other hand, the reaction product can easily be inhibited from being deposited in the dielectric wall portion at a higher heating temperature. However, a gate via which the material to be treated is supplied/removed is hermetically sealed by a rubber material such as an O-ring, or a seal member of resin. Therefore, the heating temperature is limited by the melting point of the seal member.
An object of the present invention is to provide an inductive coupling plasma processing apparatus which can be heated with a high energy efficiency in order to inhibit a reaction product from being deposited, and which can be heated without considering the melting point of a seal member for sealing a dielectric wall portion and a processing chamber.
To achieve the project, according to the present invention, there is provided an inductive coupling plasma processing apparatus comprising: a lower chamber forming a processing chamber in which a substrate to be treated is subjected to a plasma processing; an upper chamber forming an antenna chamber in which a high-frequency antenna for forming an induction field in the processing chamber by a high-frequency power supplied from the outside is disposed; a dielectric wall partioning the upper chamber from the lower chamber; a shower head portion comprising an ejection port for ejecting a process gas and a gas channel, provided in the processing chamber; insulating means attached to the surface of the dielectric wall portion on a side of the processing chamber; heating means disposed on the surface of the insulating means on the processing chamber side; and a cover member formed of a dielectric material attached to the heating means on the processing chamber side, wherein the insulating means prevents heat generated from the heating means from being conducted to the dielectric wall portion, and the heating means heats the cover member at a temperature at which a reaction product generated by a plasma is prevented from adhering to the cover member.
The insulating means comprises an insulating member formed by the dielectric material held between the dielectric wall portion and the heating means. Moreover, the insulating means has a gap disposed between the dielectric wall portion and the heating means.
Furthermore, there is provided an inductive coupling plasma processing apparatus including a processing chamber in which a plasma is generated in an atmosphere including a process gas, a high-frequency antenna for receiving high-frequency power and generating an inductive electric field in the processing chamber, and a dielectric wall disposed to contact the plasma, the inductive coupling plasma processing apparatus comprising: a cover member disposed to prevent a main portion of the dielectric wall portion from being exposed in the processing chamber, and formed of a dielectric material; heating means for heating the cover member at a temperature at which a reaction product produced by the plasma generated in the processing chamber is inhibited from adhering to the cover member; and insulating means for preventing a heat generated by the heating means from being conducted to the dielectric wall portion.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.